Process for the manufacture of solid-fashioned bodies containing silicon carbid.



I To all whom it may concern:

i sTA Es PATENT OFFICE.

.enone EGLY, OFTGHABLOTTENBURG, GERMANY, AssIeNon r GEBR. SIEMENS 8:00..

' i or GHARLOTTENBURG, GERMANY.

rnocn'ss FdR THE MANUFACTURE 01? Be it known that I, Gnono EGLY, asubject of the German Emperor, residing at 70 Kantstrasse,Charlottenburg, near Berlin, in the German Empire, chemist,have'invented certain new and useful Improvements in Processes for theManufacture of Solid- Fashioned Bodies Containing Silicon Carbid, ofwhich the following .is a specifica"- tion.

Attempts have frequently been made to render sllicon carbid(carborundum) useful for various purposes, and particularly for bodieswhich are to be heated electrically,

such as rods, tubes or the like, for which purpose the silicon carbidmust be brought into the desired form. 'The introduction of siliconcarbid for such pur oses, however, has hitherto met with the dlfl'icultythat it has not been possible to fashion silicon carbid into formshaving the properties necessary for the use to which they. are to beput. For

. many uses, as grindstones, for instance, the

I imanner. have relatively little solidity and are powdered siliconcarbid. has been mixed with a considerable proportion of an agglutinantsuch as clay; but bodies fashioned in this generally very porous;moreover, their electrical conductivity is exceedingly small or does notexist.

The present invention relates to the manufacture'ofbodies containingsilicon and carbon which are not only good electrical conductors, butareat thesame time dense, solid, mechanically strong and capable ofwithstanding chemical agents and high temperato re.

The invention consists in mixing the siliicon carbid with uncombinedsilicon. The slhcon carbld and sllic'on are mixed as 1nt1- mately aspossible and fashioned into the desired form. As an aid for this purposemay be used any suitable agglutinant, preferably one which is volatile,such as glycerin; or the agglutinant may be a material which willcarbonize when heated, as the separated carbon combines with the siliconin the mass when the. form is subsequently heated. Obviously, theagglutinant mayalso be one which will remain wholly or in part in theform after it has been heated,

such as clay or boric acid. Generally speak 'ing, however, foreignmatter of this kind is undesirable, as it may easily depreciate theSOLID-FASHIONED BODIES CONTAINING SILICON Patented Dec. 19, 1911.

Application filed October 16, 1905. Serial No.'283,051.

goodproperties which the" f rm consisting of silicon and silicon carbidalone otherwise possesses. When boric. acid is used as the agglutinant,it is advantageous to dissolve it first in glycerin, whereby it isdistributed throughout the mass as uniformly as pos sible. The glycerinis especially useful in that it makes-the mass very plastic andslippery, so that it is easily fashioned and may be squirted int-ostrings or threads. When the mass of silicon and silicon carbid has beenfashioned it is strongly heated, preferably in an indifferentatmosphere, for instance, in an electric furnace, to such a temperaturethat the mass is fritted together to a body as homogeneous andnon-porous as possible. Bodies prepared in this manner are distinguishedby their high density, resistance to high temperatures, good electricalconductivity and greathardness. They suffer sudden changes oftemperature without damage; for example, bodies madefin this manner maybe s rinkled with water, while they are at a bright-red heat, withoutdeveloping cracks or flaws, or being otherwise damaged. Moreover, theyare well able to withstand powerful chemical. agents, like chlorin orconcentrated acids, so that they may be used with advantage inelectrolytic processes wherein chlorin is liberated.-

It is obvious that, although in the foregoing specification themanufacture has been described as consisting in mixing silicon withsilicon carbid previously prepared, with or without an agglutinant, theinvention also includes the case in which the silicon carbid is producedin the form itself, while this is being heated. For instance, if carbonor carbonaceous material be mixed with more silicon than is essential toform silicon carbid, with or without an agglutinant and the mixture befashioned and heated as already described, the form produced will havethe same properties as if it had been made as hereinbefore described.

What I claim as my invention, and desire to secure by Letters Patent is:

1. A process for the manufacture of fashioned solid bodies containingsilicon and carbon, consisting in' fashioning the body from a mixturecontaining silicon carbid and silicon, the silicon being in excess ofthat required to form silicon carbid with the carbon and heatingthefashioned body.

2. A process for the manufacture of fashioned solid bodies containingsilicon carbid consisting in fashioning the form from a mixture ofpowdered silicon carbid and silicon and heating the form thus fashioned.

3. A process for the manufacture of fashioned solid bodies containingsilicon carbid consisting in fashioning the form from a mixture ofpowdered silicon carbid, powdered silicon and an agglutinant and heatingthe form thus fashioned.

4. A process forthe manufacture of fashioned solid bodies containingsilicon carbid consisting in fashioning the form from a mixture ofpowdered silicon carbidt' pow- 15 dered silicon and glycerin and heatingthe. I

' form thus fashioned.

two subscribing witnesses.

" GEORG EGLY.

Witnesses HENRY HAsrEn, WOLDEMAR

